Hi I recently bought an fzr400 that already had the fuel tank cover, fairing, exhaust off, I also took the airbox off. I went to start it and the bike turnsover but won't start. I found that I had no fuel flow, and found out it was a blocked fuel filter so thats been replaced. I have checked that there is fuel flow into the carbs and thats fine now. The spark plugs are new and the spark's good. I have tried putting fuel straight in the top of the carbs and it makes more of an effort of starting but still doesn't. Is there something I should check next?

ht leads the right way round? are the plugs getting wet?

the ht leads are going 1,2,3,4 from the left
and the spark plugs smell of petrol when you take them out

How fast does the engine turn over,does it seem to spin fast, does it feel it has compression.

A compression test would be the best thing to esablish if the engine is ok.

But lets say you have a good compression.

you'll need the air box off, the fuel tank on (and the carbs cleaned). Put a pair of jump leads or a strt pack on the battery (The car doesn't have to be running). Put a good squirt of carb cleaner down the carbs, lift the slides and put it under them. choke off.
Hold the starter button on and gently open the throttle a bit and keep the carb cleaner sparyed over the open carb intakes. After a while you'll hear the engingine turn over quicker and quiker before it starts to catch ... keep the starter and carb cleaner going and the eginge will catch more .... eventually the enginge should run on it's own on the throttle ... open the choke and see if will go on that.

It's not a nice thing to do to an engine.

If it flatly refuses to start then you'll probably fing the valve clearances have closed to zero